DanielWang2035 commented on code in PR #17238: URL: https://github.com/apache/iotdb/pull/17238#discussion_r3278711861
########## iotdb-core/consensus/src/main/java/org/apache/iotdb/consensus/iot/WriterSafeFrontierTracker.java: ########## @@ -0,0 +1,188 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ + +package org.apache.iotdb.consensus.iot; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.util.Collections; +import java.util.HashMap; +import java.util.Map; +import java.util.Objects; + +/** + * Tracks per-writer safe frontier on the receiving side. + * + * <p>Each writer keeps at most one pending safeHLC because generated safeHLC for the same writer is + * expected to be totally ordered by both safePt and barrierLocalSeq. + */ +public class WriterSafeFrontierTracker { + + private static final Logger LOGGER = LoggerFactory.getLogger(WriterSafeFrontierTracker.class); + + private final Map<WriterIdentity, WriterFrontierState> states = new HashMap<>(); + + public synchronized void recordAppliedProgress( + final long physicalTime, final int writerNodeId, final long appliedLocalSeq) { + final WriterIdentity writerIdentity = new WriterIdentity(writerNodeId); + final WriterFrontierState state = + states.computeIfAbsent(writerIdentity, ignored -> new WriterFrontierState()); + state.appliedLocalSeq = Math.max(state.appliedLocalSeq, appliedLocalSeq); + if (physicalTime > 0) { + state.effectiveSafePt = Math.max(state.effectiveSafePt, physicalTime); + } + promotePendingIfReady(state); + } + + public synchronized void observePendingSafeHlc( + final long safePhysicalTime, final int writerNodeId, final long barrierLocalSeq) { + if (safePhysicalTime <= 0) { + return; + } + final WriterIdentity writerIdentity = new WriterIdentity(writerNodeId); + final WriterFrontierState state = + states.computeIfAbsent(writerIdentity, ignored -> new WriterFrontierState()); + final SafeHlc candidate = new SafeHlc(safePhysicalTime, barrierLocalSeq); + if (state.appliedLocalSeq >= barrierLocalSeq) { + state.effectiveSafePt = Math.max(state.effectiveSafePt, safePhysicalTime); + state.pendingSafeHlc = null; + return; + } + if (state.pendingSafeHlc == null) { + state.pendingSafeHlc = candidate; + return; + } + final SafeHlc pending = state.pendingSafeHlc; + if (dominates(candidate, pending)) { + state.pendingSafeHlc = candidate; + return; + } + if (dominates(pending, candidate)) { + return; + } + LOGGER.warn( + "Observed incomparable safeHLC for writer {}. keep pending={}, ignore candidate={}", + writerIdentity, + pending, + candidate); + } + + public synchronized long getEffectiveSafePt(final int writerNodeId) { + final WriterFrontierState state = states.get(new WriterIdentity(writerNodeId)); + return Objects.nonNull(state) ? state.effectiveSafePt : 0L; + } + + public synchronized SafeHlc getPendingSafeHlc(final int writerNodeId) { + final WriterFrontierState state = states.get(new WriterIdentity(writerNodeId)); + return Objects.nonNull(state) ? state.pendingSafeHlc : null; + } + + public synchronized Map<WriterIdentity, Long> snapshotEffectiveSafePts() { + final Map<WriterIdentity, Long> snapshot = new HashMap<>(); + for (final Map.Entry<WriterIdentity, WriterFrontierState> entry : states.entrySet()) { + snapshot.put(entry.getKey(), entry.getValue().effectiveSafePt); + } + return Collections.unmodifiableMap(snapshot); + } + + private void promotePendingIfReady(final WriterFrontierState state) { + if (state.pendingSafeHlc == null) { + return; + } + if (state.appliedLocalSeq >= state.pendingSafeHlc.getBarrierLocalSeq()) { + state.effectiveSafePt = + Math.max(state.effectiveSafePt, state.pendingSafeHlc.getSafePhysicalTime()); + state.pendingSafeHlc = null; + } + } + + private static boolean dominates(final SafeHlc left, final SafeHlc right) { + return left.safePhysicalTime >= right.safePhysicalTime + && left.barrierLocalSeq >= right.barrierLocalSeq; + } + + public static final class WriterIdentity { + private final int writerNodeId; + + public WriterIdentity(final int writerNodeId) { + this.writerNodeId = writerNodeId; + } + + public int getWriterNodeId() { + return writerNodeId; + } + + @Override + public boolean equals(final Object obj) { + if (this == obj) { + return true; + } + if (!(obj instanceof WriterIdentity)) { + return false; + } + final WriterIdentity that = (WriterIdentity) obj; + return writerNodeId == that.writerNodeId; + } + + @Override + public int hashCode() { + return Objects.hash(writerNodeId); + } + + @Override + public String toString() { + return "WriterIdentity{" + "writerNodeId=" + writerNodeId + '}'; + } + } Review Comment: Removed -- This is an automated message from the Apache Git Service. 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